The present invention relates to a squirrel-cage rotor of an asynchronous machine, and to a method for producing such a squirrel-cage rotor.
The following discussion of related art is provided to assist the reader in understanding the advantages of the invention, and is not to be construed as an admission that this related art is prior art to this invention.
Squirrel-cage rotors of asynchronous machines, also referred to as cage rotors, are exposed to the risk, particularly at high rotational speeds, of their short-circuit rings, which are arranged on the axial ends of the laminated core, bending or even breaking on account of centrifugal forces. For example, U.S. Pat. No. 5,719,457 proposes to control centrifugal forces in the region of the short-circuit rings, which is axially distanced from a laminated core, by pushing shrink rings over the short-circuit rings.
DE 199 27 279 A1 proposes interference fit assemblies of a short-circuit ring which is axially distanced from the laminated core to absorb the centrifugal forces of the short-circuit ring.
DE 10 2005 030 798 A1 discloses a rotor of an asynchronous machine, having short-circuit rings available directly on the front faces of a laminated core, wherein the laminated core has grooves for receiving short-circuit rods, wherein the short-circuit rods on the respective front faces are connected by the short-circuit ring and wherein additional profiled sheets exist in the region of the short-circuit ring, which are used to pack the laminated core and to absorb the centrifugal forces of the short-circuit ring.
Common to all conventional solutions is the fact that they are relatively complicated and thus costly in terms of their realization. Shrink rings or interference fit assemblies cause mechanical stresses in the affected components, which, as experience has shown, come into play after a period of operation and thus cause geometric changes in the rotor which negatively affect the original smoothness of the squirrel-cage rotor.
It would therefore be desirable and advantageous to provide an improved squirrel-cage rotor for an asynchronous machine to obviate prior art shortcomings and to be applicable for high rotational speeds, while yet being simple in structure and effectively ensuring absorption of forces occurring particularly in the region of the short-circuit ring at high rotational speeds of the squirrel-cage rotor.